1. Field of the Invention
The present invention relates to image capturing apparatus useable in digital cameras which include a solid-state image capturing element which outputs charge signals for one horizontal line in a predetermined order of arrangement different from that of pixels on a corresponding horizontal line on a photosensitive surface of the camera. The present invention also relates to an image capturing method.
2. Background Art
Conventionally, many CCDs are used as an image capturing element in image capturing apparatus such as digital cameras. In such CCD, charge signals on pixels arranged on horizontal parallel lines on a photosensitive surface of the CCD 1 are usually transferred in units of a line simultaneously to a horizontal transfer path and then swept away out of the CCD in accordance with a horizontal sync signal. This operation is repeated such that data on all the pixels are outputted with their arrangement order maintained.
A CCD is known which includes an array of pixels each with a color filter in its light path and operates such that the CCD adds (or mixes) charge signals on each adjacent pair of pixels having the same color filters arranged on a respective vertical line (but one pixel of any adjacent pair used for the signal addition is not used as a pixel of another adjacent pair) and reads resulting signals, in order to reduce a time required to process the image signals outputted from the CCD, for example, when a moving image of a subject is captured (as disclosed in Published Unexamined Japanese Patent Application TOKKAIHEI 9-18792).
Recently, in order to perform a series of processing operations at high speeds on image data added and read in a manner mentioned above, a CCD has been thought out which sweeps away charge signals on the respective pixels arranged on each horizontal line on the photosensitive surface of the CCD and added within the CCD while maintaining the actual order of arrangement of those charge signals on the horizontal line.
When charge signals on all the pixels are read without being added in this CCD, however, the charge signals on pixels arranged on each horizontal line on the photosensitive surface of the CCD are required to be divided into a plurality of groups which are then swept away sequentially with respective successive horizontal sync timing signals. As a result, a captured image signal for one horizontal line outputted from the CCD includes charge signals arranged in a different order from that in which the pixels are actually arranged on the photosensitive surface and various processing operations to be performed on the read image signal would be complicated.
It is therefore an object of the present invention to provide an image capturing apparatus and method for performing various processing operations on the read image signals efficiently even when a solid-state image capturing element is used which outputs charge signals for one horizontal line arranged in a predetermined order different from that in which the pixels are actually arranged in a corresponding line on the photosensitive surface of the element.